Our ever-busy president, Nicolas Sarkozy, has been banging on about it since even before he was elected, and this week his finance minister – boss of a big Chicago law firm in a former life – was even plainer: we French do not work hard enough. "Instead of thinking about their work, people are thinking about their weekend, organising, planning and engineering time off," Christine Lagarde told the BBC. It's time for the nation to "roll up its sleeves" and get back to work.

Her call followed the results of a survey by a Swiss bank which found that the average French man or woman spends a mere 1,480 hours a year doing their job, and enjoys a staggering 27 days' annual holiday, making the French officially the least hardworking nation on earth. The Brits, by contrast, put in 1,782 hours a year and have 20 days' holiday. It's a view Nicolas Sarkozy has long held dear: France's work ethic is "in crisis", he is fond of saying.

Fair enough. Of course we don't work. We have a much-mocked law preventing us from working more than 35 hours a week, don't we? We're entitled to a legal minimum of five weeks' annual holiday (plus all those bank holidays), and many of us get eight weeks or more. In the civil service, in education, and in some of the big state-owned transport outfits like the Paris metro and the SNCF, some of us have it even cushier: up to 11 or 12 weeks holiday, a 32-hour week, retirement at 50. We don't, in general, work on Sundays. Oh, and we all have long, languid and liquid lunches.

We French just love the idea of getting away with doing as little as possible. In 2004, a young electricity board employee called Corinne Maier wrote a little book called Bonjour Paresse (Hello Laziness), subtitled "On the art and necessity of doing the strict minimum for your company". Her argument, in essence, was that your employer can fire you whenever it chooses, and that you therefore owe it nothing (or at least, not very much). Naturally, it became an instant bestseller in France. We adored it.

The odd thing is, though, that when we do work, we're not that bad at it: French productivity per hour is among the highest in the world, ahead of workers in Britain, Germany, the US and Japan. And it's not even true that we don't work long hours: try telling that to lots of people in the private sector, and particularly small business owners – one recent study showed the bosses of small French companies put in an average 59 hours a week, compared to 54 hours in the UK and 52 in America.

True, a lot of young French people come to London and land jobs they wouldn't find in France. They praise Britain's entrepreneurial spirit, can-do attitudes and hard work ethic, as well as the fact that in general, you're recognised here for what you can do rather than what qualification you've got. But it's noticeable that unless they're on an expat package, once they have children they head back to France as soon as they can. Cheap childcare? That's in France. The world's best universal healthcare? France too. Schools that parents don't worry about? Public transport that works? Ditto. It's a quality of life thing, really.

And though there are undeniably many French employees, particularly in parts of the public sector, that only very rarely put in what most of the rest of the world would consider a good day's work, there are many more who work very hard indeed. It's just that we see that work-life balance rather differently to you. We'll take our holidays, and our lunch hours, because we enjoy them (and they might, just, help us work better than if we didn't take them).

So it's a bit disingenuous of Christine Lagarde to tell us we need to roll our sleeves up. There's little real evidence to suggest the relationship the French have with their work is in decline, or that the French value their work any less than they did. Or at least, I can't find any. What she and her boss are really doing is just reasserting a debatable claim that they hope will help create the kind of climate in which their free-market policies will be more widely accepted. It's politics, that's all.